1. Field of the Invention
The present invention pertains to the field of controlling power consumption in a system such as a computer system. More particularly, the present invention pertains to controlling the rate of change of current consumption for one or more electronic devices.
2. Description of Related Art
By controlling or limiting the rate of change of current consumption for an electronic device, one may advantageously reduce the cost and/or size of the power supply required to operate that device. In fact, the ability of a power supply to respond to instantaneous or rapid changes in power demand is a significant constraint on the design of the power supply. As a result, a large and/or expensive power supply may be necessary if the system requires the power supply to respond very quickly to large changes in current demand.
Additionally, as microprocessors and other electronic components provide new features and/or process larger quantities of data, power consumption typically rises, further burdening power supplies. Numerous power saving techniques combat this general tendency of increased power consumption. For example, as semiconductor processing technologies advance, smaller transistors which consume less power may be used. components may also include logic dedicated to reducing power consumption. For example, some microprocessors include pins such as stopclock pin which (when asserted) stops the clock of the processor or a portion thereof. Toggling such pins may dramatically change the power consumption of the processor in a relatively short order of time.
Another technique known in the art is clock gating. Clock gating generally refers to disabling the clock signal(s) to a portion of a processor or other electronic component in which no activity is occurring. Stopping the clock(s) for such inactive portions saves power without impacting performance because clocks are again enabled when the disabled portion of the component is needed. Relatively large portions of a component may have gated clocks, therefore clock gating also can dramatically impact power consumption in a very short order of time.
Thus, at least stopclock pin assertion and clock gating can advantageously cause dramatic power savings by quickly reducing unnecessary power consumption. Unfortunately, these power saving measures place additional constraints on power supply designs due to the often sizable and rapid changes in current involved. Nonetheless, power supplies typically need to tolerate such rapid and dramatic changes in current consumption while remaining within a specified voltage range. As a result, power supplies may be unnecessarily large and/or expensive. Controlling the rate of change of current consumption of electronic components or portions thereof may allow systems to operate using power supplies with less stringent specifications, potentially reducing cost and/or size.